Method and apparatus for obtaining indicator diagrams



NOV. 11, 1930. H M JACKLlN ET AL 1,781,013

METHOD AND APPARATUS FOR OBTAINING INDICATORADIAGRAMS Filed March l5, 1926 l 3 Sheets-Sheet l I N V EN TORS Hara/d /7 c/ac//m Char/es P Rober/i5.

Nov. 11,V 1930. H. M. JACKLIN ET AL 1,781,013

METHOD AND APPARATUS FOR OBTAINING INDICATOR DIAGRAMS Filed March l5, 1926 3 Sheets-Sheet 2 IN V EN TOR. Haro/0' M Jack/ln. Char/es P /Poberf' TToRNEY Nov. 1l, 1930r H,v M, JACKLIN ET AL METHOD AND APPARATUS FOR OBTAINING INDICATOR DIAGRAMS Filed March l5, 1926 5 Sheets--Sheei'I 5 COMBUSTION EXPANSION INTAKE STOP ATMosPr-xsrruc INTAKE l N V EN TOR5 A Haro/a M Jack/1n. Char/e5 Rob er/s.

Patented Nov. 11, 1930 narran STATES PATENT OFFEQE HRLD M. JACKLIN AND C TrIABJESy P. EGBERTS, 0F COLUMBUS, OHIO; SAD ROBERTS ASSEGNO-R TO SAD' JA'CKLIN .METHOD ANDv APPARATUS FOR OBTINNG NDICATOR DIAGRAMS Application inea Maren 15, i926.

Our invention relates to a ire paratus tor obtaining ind etor diagrams and has to do'particularly W th the provision of a novel and accurate means for obtainirfa,` indicator diagrams from high speed, multicylinder Vinternal combustion engines.

t has long been recognized in the art that indicator diagrams are only useful and efficient When'the resulting record ol1 the'pressures Within the cylinder directly indicates the various pressures or events in such cylinder in synchronism With the mot-ion ot the piston. in the past, various methods and means have been used and designed to accurately record the various pressures or events in the cylinder in synchronism. With the motion oi' the piston, but the majority ofthe devices used have only been accurate when properly installed and used on engines designed to operate at comparatively low speeds as for instance, when used in combination with steam engines running at constant load. llhen these indicators have been used on internal combustion engines at low speeds and at constant loads, it has been necessary to obtain as many diagrams as p0ssible during a test in order to obtain an approximate average. This has been necessary because oi the great variations in operation from cycle to cycle even when operating conditions were ideal. Efforts to use these indicators on internal combustion engines at high speeds, Where rather sudden changes in pressure occur, result in the obtaining ci unsatisfactory diagrams due to the ia ct that, because ot this speed and sudden changes in pressure, the inertia of the indicator piston, the springs, links, pencil, drum, and drum driving mechanism enter in as factors giving a very inaccurate record.

Attempts have been made to reduce the inertia of the parts ot an indicator by arranging to deflect a beam o'f light on a ground glass or photographic negative by means of a mechanically and pressure operated mirror orV mirrors which need move very little for a. great` deflection of the beam of light. Besides having the drawback of requiring photographic process to obtain a permanent record which may be distorted during these thod :and ap- Serial No. 94,776.

same processes7 such devices have not been snccessiul on engines Whose speed approximates one thousand or higher revolutions per minute.

l efforts in the past to obtain indicator diagrams from high speed engines and particularly high speed automotive engines, have not only tailed because ci the great inertia oit parts resulting from such high speed, but also for the reason that such diagrams have shown but one complete cycle. i diagram ot but one complete cycle may or may not be an err-ge diagram underthe conditions of operaiion of the engine. A diagram representing a single cycle may be representative of approximate average conditions of a steam engine running at constant load. but a diagram ot a single cycle oit a high speed internal combustion engine, if the diagram could possibly be obtained, might not be representative ot the average conditions Which might exist in the cylinder, cycle to cycle.

Our aim is an entirely novel method of quickly and accurately obtaining an indicator diagram Which, in itself, Will correctly shoiv the variations from cycle to cycle in any given cylinder ot a lgh speed internal combustion engine over several cycles. This novel method of obtaining indicator diams shovving the variations in conditions in high speed internal combustion engine cylinders, is accomplished by the provision ot a simple and compact structure which may be connected to one or all of the cylinders of an internal combustion engine, and which is so constructed and operated as to be unaffected by any inertia eilects in the indicator itself, and which is so constructed in combination with the operation of the engine, that the indicator diagram Will be built up section by section so as to form a complete indicator diagram correctly showing the variation in conditions in the engine cylinder in exact synchronism with the mov ments of the piston in such cylinder.

One of the objects of our invention is the provision of an engine indicator for graphically describing by diagram the variations of pressure in the engine cylinder of a high speed engine, over a period of cycles.

Another object of our invention has'to do with the provision of a novel device for insuring the indicatonof a particular event of pressure in the cvlinder in exact synchronism with the movement of the piston in such cylinder. In other words,rwe have. provided a device whereby, regardless of the time that pressure is admitted to the indicator, or regardless Vof the time that this pressure is marked on' the diagram, such indication of pressure or event will be in synchronism with the position of the piston in the cylinder at the time of taking of such pressure or event.

A further object of our invention has to do withthe provision of means for automatt cally admitting pressure to the indicator in proportionate synchronism with the revolutions per' minute of the engme shaftand a differential structure for gradually changing the particular point in the engine cycle to be recorded'upon the particular card. The

' result is Vthat a graphic diagram is built up,

section by section, each section being taken from a separate cycle and Vrecorded in its correct sequence and position on-the diagram and at a point corresponding exactly to the instantaneous position ofthe piston in the engine cylinder. The graphic diagram, thus Abuilt up, section by section, is a composite diagram of theconditions obtained in the cylinder being tested over severalhundred cycles.

YAnother object of our invention contemplates the provision of means for admitting the effective pressure of the cylinder to the indicator structure for only a small instant of time, and means for moving the point in the cycle at which the valve is open and for gradually advancing the paper upon which the diagram is described. In this way, a

Ysmall section of the final diagram is taken Yduring each cycle of events in the engine cylinder and as the point in the cycle at which the pressure is admitted is varied, the paper an which the diagram' is described is moved so that the new sections are recorded at points rator cylinderwith oil not onlyV reduces the ealtage past the indicator piston. but also presents' a means for reducing the clearance space in the indicator cylinder and thus requiring the transfer of an almost minute Quantity of gases during the time the admission valve is open. Y

A further objectof our invention has to do with the provision of novel cooling meansV for the gases being transferred from the engine cylinder to the indicator cylinder. By

thus providing posit-ive cooling means for theV gases being transferred, it will be possible to indicate the variations in pressure in internal combustion engine cylinders Without interference because of pre-ignition in the connecting tubes. Y

Many other features of ourinvention, such as various adjustments for adapting the indicator to various conditions and for rendering the indicator precise and accurate under all conditions, will be apparent as this Ydescription progresses and will be brought out in the claims appended hereto. The various objects of our invention are preferably obtained by the structures illustrated in the drawings wherein similar characters of reference designate corresponding parts and wherein- Figure 1 is a perspective view partly cut away and partly 1n section, of our novel indieating device and showing in detail the cam mechanism for admitting the gases to the indicator cylinder and the diiferential mechanism for controlling` the relative position of the opening cam and driving shaft and for insuring positive synchronism between the movementsof the indicator pencil and `drum and the movement of the pistoninthe engine cylinder.

Figure 2 is a. fragmentary detail view -of the structure for frictionally engaging the differential housing to normally prevent turning' movement thereof.

Figure 3 is a. detail view of a preferred type of'tube or plug for insertion into the engine cylinder to be tested, and showing one manner of cooling such plug to V prevent overheating. V

Figure 4 illustrates a conventional diagram taken from the cylinder of a high speed internal combustion engine and such diagram showing the variation in conditions in such cylinder. Y

Figure 5 illustrates aQOOdiagram taken from the same cylinder operating under the same conditions as the diagram in Figure 4, This diagram was taken by shifting the crank for controlling the movement of the indicator drum t0 a point 90 from the point used in making the diagram in Figure 4 in order to obtain a 'diagram which shows the combustion line more in detail.

Figure 6 is a fragmentary sectional plan view taken through the valve operating mechanism showing the arrangementof the cam and cam follower for actuating the indicator valve.

Figure 7 is a plan view of ra manifold or valve boX for connecting the indicator structurewith the various cylinders of a` multicylinder engin-e whereby it is possible to connect a selected cylinderY to the indicator valve.

Figure 8 is a transverse section taken on line 8 8 of Figure 7 and showing the general arrangement of valvestructureV for admitting and transferring -thegases from the lue .engine cylinder and also showing the manner of cooling the manifold or valve boa.

l1 igure 9 is a view showing the clutch mechanism whereby it is possible to change the point in the cycle at which the valve is opened and to operate the drum control mechanism either manually or mechanically.

Figure 10 a so-called lower loop diagram obtained from a four-stroke cycle engine when using a very light spring and a stop for the protection of the spring in a conventional slow speed indicator in combination with our device. It is an enlarged picture of the lower part of Figure 4 wherein it is possible to see the vvariations in pressure during the exhaust and intake strokes more in detail.

In describing the various parts of our invention. it will be well to r ,cognize that the apparatus preferably used therein is separable broadly into an adjusting and synchronizing mechanism and an indicating mechanism. There are also certain minor combinations forming a. part of either of said two main combinations, and particularly of said adjusting and synchronizing mechanism.

The main purpose of this adjusting and synchronizing mechanism is to accurately and precisely adjust and control the movements of the parts of the indicating device in exact synchronism with the movements and speed of the internal combustion engine but at a much lower speed so that all inertia effects are removed. ln Figure 1, the adjusting and synchronizing device is shown as a single unit connected to the indicating device. r1`his adjusting and synchronizing device is operated by a main driving shaft 1 which is designed to be driven by the particular engine to be tested through the medium of suitable gears or chain and sprockets or other means whereby the shaft 1 rotates continuously at a certain lined relation to the speed of the engine. In the preferred operation of this device, this shaft 1 must he so geared to the engine crank shaft that such shaft 1 will rotate at one-half the speed of the engine crank shaft if suoli engine is operating on the four-stroke cycle. Shaft 1 should be operated at engine crank shaft speed when testing a two-stroke cycle engine, and when testing a six-stroke cycle engine if such were desired, the shaft 1 should rotate at one-third the crank shaft speed.

rlie main driving shaft 1 is directly connected to the driving gear 2 of a standard diderential gear construction. These differential gears, as illustrated in Figure 1, arey mounted in a differential gear case 3 which is adapted to be rotated within the main housing l of this adjusting and synchronizing device. The driven gear 5 of the differential gear construction is keyed to a shaft 6, shown in dotted lines in Figure 1, which shaft extends upwardly within the housing` i 4.' Secured to the upper end of this shaft 6, by means of suitable keys or pins, is a slotted disc 7. Adjustably mounted on the under side of said disc 7, by means of screws 8, is a second disc or connecting collar 9 which is provided with a hollow extension 10.

Keyed to the hollow entension 10 of this adjustably supported disc 9 is a cani disc 11 provided with a cam element 12. This cam element 12 directly controls the opening` of the valve for completing communication between the engine cylinder' and the indicator cylinder as will be later described. It will be obvious that the cam disc 11 and cam 12 rotate in a direction opposite to the rotation of the main shaft 1 and at the same speed as the shaft 1 so long as the differential gear case 3 remains stationary.

This differential gear case 3 is provided at its upper end with a spur gear 13. The movement of this spur gea-r 13 and the differential housing 3 is controlled hy pinion 14 which is secured to a shaft 15 carried by the main housing 4. Secured to the base of this shaft 15 is a worm wheel 16 designeci to be driven by a suitable worm 17 mounted upon a shaft 18. The shaft 18 is provided with a crank 19. The shaft 18 is also provided with a suitable worm wheel 2O which is designed to mesh with av worm 21 keyed to the shaft 1 and which worm wheel 20 is ordinarily free to rotate on shaft 18. The shaft 18 is preferably provided with al jaw, or other standard type of clutch, as shown engaged in Figure 9 which is adapted to engage the worm wheel 2O when the shaft 18 is moved axially outward by means of the crank 19. Thus, by moving the shaft 18 aX- ially outward, the clutch will engage with the worm wheel 2O and cause shaft 18 to be turned by the shaft 1 through the worm 21 and worm wheel 20. By moving this shaft 18 inwardly, the said clutch may be disengaged and the worm 17 moved manually by means of the crank 19.

The upper end of the shaft 15 is provided with crank disc Thus, it will be obvious that thecrank disc 22 and the different-ial drive pinion 14 are both moved and directly controlled by the shaft 15. lVhen testing a four-stroke cycle engine, the ratio between gears 13 and 14 should be el to 1; when testing a two-stroke cycle engine, the ratio should be 2 to 1, and on a six-stroke cycle engine, this ratio should be 6 to 1.

rlhe crank disc 22 is preferably provided with a series of holes 23, preferably twentyfour in number, which are circumferentially arranged adjacent to the periphery of the disc. The twenty-four holes are provided so that the indicating device may be used on any multi-cylinder engine where the firing intervals are multiples of 15. lt will be understood that these holes 23 may be changed so that diagrams may be-taken offset the same 1n the ratio of the throw of from multi-cylinder engines whoseliring intervals 'are not in multiples of 150, but in other multiples as maybe desired.

The crank disc 22is provided with a crank arm 24 to which is pivoted one end of a connecting rod 25. The crank arm 24 may be located in any desired position by means of a crank pin 26 which may be pushed down,

through the end of the connecting rod and the crank arm in registry with any one of theholes 23. It will be understood that the ratio between the length of the connecting rod and the throw of the crank arm 24 is hole-'723. -Any suitable mechanism may beV used for adjusting the ratio between the connecting rod 25 and the crank arm 24, as for instance, the connecting rod 25 itself may be adjustable in length, or different lengths of connecting rods may be used as replacement units.

The other end of the connecting rod 25 is pivotal-ly connected to a crosshead 28 which is adapted to slide upon the crosshead guide 29. This crosshead guide is provided with an aperture guide 30 and a suitable ypulley 31 for forming an intermediate support for an indicator cordr32 one end of which is preferably connected to a suitable projection 33 on the crosshead 28. The swivel or pulley 3l is preferably adjustable to permit the ,cord to be used with and correctly directed towards any type of standard slow speed indicator. The cross head guide 29 is adjustably mounted upon the frame 34 by means of slots andscrews 35 whereby it is possible to arrange the center line of the crosshead guide in alignment with the center of the crank disc 22 and the hole 27 or to the crank arm-24 to the throw of the crank of the engine to be tested should the engine have odset cylinders. This is then done so that the crosshead 28 will simulate the exact motion of the piston in the engine cylinder. upon the upper part of the housing 4 or may form an integral part thereof.

The frame 84 is also designed to receive and support a valve housing 86 to which may be attached any typeof slow speed indicator. the valve housing V36 by `means of a suitable union j This indicator is shown pro- The frame 34 may be mountedV An indicator is shown connected to vided with. the customary piston 38 which skilled in the art. f s

The housing 36 is secured to the frame 34 by means of a nut 41 and the' indicator and housing may be set to any desired position for the taking of diagrams merely by loosening this nut 41 and adjusting the housing and indicator cord 32. c This housing 36 is provided with a longitudinal opening for the reception of av valve 42 and a valve stem 43. Tt being understood that it is a part of our invention to partially fill the indicator cylinder with a supply of oil in order to reduce the clearance space in such indicator cylinder and thus reduce the quantity of gases to be introduced into such cylinder by the opening' of the valve 42, it is apparent that j this oil may be introduced by disconnecting the union 37, and that'the valve housing `36 should be so set that the indicator cylinder points downward, thus retaining the oil above the indicator piston 38.

As is shown in Figure 6, the cam element 12 is designed to strike the cam roller 48, carried Vby the cam follower 45 one end of which is pivoted on an eccentric shaft 46. rThis shaft 46 extends upwardly in the main housing 4 and is keyed at its upper endto a lever 47 Figure 1 which may be moved in an arc and locked in either one of two positions 'by means of a suitable pin similar to pin 26 as is clearly shown in Figure 1. At one position of the lever 47, the cam follower 45 will be resiliently held against the cam 12, while in the other position of the lever 47, the cam follower will be moved away from the'cam 12 due to the eccentricity of the shaft 46. The cam follower45 is provided Vwith a smallv roller 48 against ywhich the cam 12 contacts and at its other end the cam follower is provided with a secondrroller 49`v which bears against Van adjustabletappet 50 forv actuating the valve 42 through the valve stem 43. The cam follower is moved towards the cam 12 and against an adjustable stop 51 by means of a suitable' spring 52 carried by the housing 4. This adjustable stop 51 limits the return movement of the follower 45 and can obviously be adjusted so that the valve will close properly. It will also be obvious that if the valve tappet 50 is adjusted to be made longer or shorter, the

valve 42 may be adjustably opened to different degrees of lift.

The valve stern 43 of the valve 42 is properly .Y provided with oil` grooves, passes,

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Ithrough andis closely-fitted into the valve housing 36 so that no packing is required to prevent leakage. The valve 42 is held innormal position by means of a coil spring k55 as shown in Figure 6.

As shown in Figure 2, the housing l is preferably provided With a spring pressed plunger` Which -is positioned Within the i' ng and adapted to be resiliently forced gjnst .the wall of the differential housing 'ille purpose of this spring pressed plunger 56 is to prevent movement of the differential housing unless positively moved` by means of handle 19 o r Worm and Worm Wheel 2l and 2O through ,the clutch, as shown in Figure 9.

For the purpose of timing the device, a second locating lug or hole 57 is provided on the housing fl; in addition to the lug 27. TWith the crosshead 29 properly lined up With the center of the crank disc 22 and hole 27, and with .the length of the connecting rod 25 and crank 24 in proper ratio to the engine being tested, it is a very easy matter to time the device. The dead center of the engine having been ascertained and With the pin 26 in .any chosen hole, the `crank disc 22 is rotated so that a locating' pin may be put through a hole in Vtoe crank disc opposite to the one cho ,n and into the hole 27. By removing the screws 8, the shaft l having been connected to the engine by ,any suitable means as heretofore described, andthe engine placed on dead center, the disc 9 may then be rotated until the hole 58 registers With the hole 57, when the disc may be held by inserting a pin through hole 57 andinto the hole 5S. The cam l2 is then positioned so that it Will hold the valve open on the dead center of the engine and of the crank 24:. After the screivs or nuts have been tightened, the locating or positioning pins must be removed. To any lone at all experienced in the art, it is 'here apparent that all backlash or lost motion if any should be taken out of the mechanism and out of the drive to the engine in order to have the device correctly timed.

tube 59, Figures l and 3, for conducting gases from the engine cylinder to the valve )using 36 and thus to the indicator cylinder, provided. This tube is preferably provided with a series of flanges or discs made of copper, aluminum, or similar inaterial for or it may be enclosed in a second tube i which Water may be Vcirculated to i verheating and ignition of the gases. tube 59 may be connected to the cylinself by means of a suitable plug 60, re threaded at its lower end for proportion in the cylinder. YWater or other means may be fed to and conduct-ed aivav from Vthe plug 60 by means of suitable its 6l and 62.

.hovvn in Figure l, the device is arranged for use-on a single cylinder engine.

For obtaining indicator diagrams from a multi-cylinder engine, ive have provided a manifold or valve box 63, as shown in Figures 7 and 8, for successively obtaining indicator l' anis from different cylinders of .iithont stopping the engine or The indicatingI device. rlfhis maniaci; 63, as shown, is approxisquare in cross-section and cored to "or cooling by vvater or other means, medium being conducted thereto away from by means of conduits 64 and The center of e manifold or valve box is preferably provided with a single conduit 66, one end vfhich may be connected With .ie valve housing 36 of the indicator device. shoufn in Figure S, the air cooled conduits 5E) leading from the respective cylinders are connected to the manifold by means of suitable connection units Valves 68 are provided for each conduit 59 andare positioned in the manifold by means of elements 69, similar to the elements 67. As Will be clearly obvious in Figure. 8, the valves 68 may be moved inwardly to shut otl' the passage of gases through any of the conduits 59 Without restricting the passage of the gases from any other conduit to the valve housing 86. Thus, an indicator diagram can be taken from any one of a plurality of cylinders conveniently and quickly vvithout stopping the engine or removing the indicating device and Without danger of ignition from over-heated parts. The manifold 63 is preferably provided With valve 68, as shoivu in Figure 7, for unis-sion of atmospheric air to the indica mechanism for obtaining the atmospheric line on the indicator diagram.

In Figure 7, the manifoldfis shown for connecting a set of six cylinders to the indicating device. t Will be obvious from the above description, 'that if this Were a six cylinder, four-stroke cycle engine, with the crank pin 26 located in a correct hole 23 in the crank disc 22 for obtaining a diagram from say. cylinder No. 5, that, in order to obtain a diagram from cylinder No. 2, it would only be necessary to close the manifold valve for No. cylincer and open the corresponding valve for llo. 2 cylinder since the crank pins of cylinders 2 and 5 are always in the same plane in a conventional six cylinder, fourstroke 'cycle engine. Then, to obtain kdiagrams from cylinders l and 6, it becomes necessary to manipulate the proper valves but with the crank 24 moved around 126 on crank disc 22 and With pin 26 placed in the proper hole 23. After obtaining ldiagrams from cylinders l and 6, it isthen necessary to again move the crank 24 to a new position l2()O from the other two positions on crank disc 22 and-to manipulate the proper valves 68. ln any other multiple cylinder engine, it is necessary to have a sufficient number of valves 68, and to move the crank 24 to posivrl OO tions on the crank disc l22 corresponding to taneous posit-ion of the engine piston. In

the selected crank pins of the engine being tested.

In ythe operation of our device, an indicator vcard is placed .upon the drum 40 of the indicating mechanism and the valve for admit- V Yting the gases from the cylinder to be tested described.

is opened to admit such gases through a proper conduit 59, it being understood that Y the ratio between the connecting rod 25 and crank 24 is the same as the ratio between the connecting rod and crank of the engine and that the cam 12 and discs 22, Y and 9 have been positioned for correct timing as above lf the diagram is to be taken by hand, the shaft 1 is .connected'to the shaft ofthe engine to be tested by any suitablel means to rotate in the proper ratio. The pencil lever 39 may then be pressed against the paper on the drum 4Q. If the handle 19V of the differential housing 3 is not moved, the cam 12 will open the valve 42 at exactly the same vpoint in each cycle. However,if the shaft 1 is rotated at one-half engine speed, for instance, for testing the four-stroke cycle engine, and the crank disc 22 is rotated by moving the handle 19, the cam 12 will be gradually moved ahead or backward, as the case may be, thus striking its follower and opening the valve 42 at the dierent points in the successive cycles. -As the movement of the Ahandle 19 directly controls the movement of the disc 22 in synchronism with the advancement or retarding of the cam 12,'the paper on the drum 40 will be moved accordingly. Y

lVhen the handle 19 is moved so that the disc 22 has passed through two complete turns, the cam 12 will be in exactly the same position with reference to the shaft 1, and it will have been advanced or retarded one full turn in the process. Furthermore, while the crank disc has been making two complete turns, the

j crosshead 28 has moved twice in each direction', thus completing four complete strokes. l

As the drum is actuated by the cross head in one direction,-and by its return spring in the opposite direction, such drum will have been YYce moved twice in each direction. SinceV the valve is opened by the cam-12 foronly a short period during each cycle,and since the cam 12 makes one VVcom plete Vadvancement or re-y tardation while thecrank disc hasmadetwo complete turns, the pencil on the drum 40'V will rise and -drop according to the pressure in the engine cylinder at the timethe valve isopen, which time coincides with the time at which the crank pin of the engine corre- Vspondsexactly with the positionV of the pin.

26. Furthermore, as the 'position of the crosshead 28 is controlled by the position and Y the throw of the crank pin 26and the connecting rod 25, the :ratio'of the connecting rod Y' Vand the throw being exactly the sameasthat between 'corresponding parts in the engine, the drum 40 will Y'be moved so that the-pencil y operators.

bears on points corresponding to the simul- A other words, by these steps of operation, a,

complete diagram, asshown in Figures 4, 5 and 10, is built upV and traced on the card,i70 section by section, as the handle 19 is moved, each part being exactly'in its proper position and in exact synchronism with the engine crank and piston. As the valve opens only once in each cycle, and for a very small periodgfj that cycle, these successive parts ofthe diagram are taken over some period of time (say one minute) and such builtV ,up diagram, therefore, shows the variation in conditions existing in the cylinder during that time. 33;()k

lfit is desired to'move the disc 22'and adyvanc'e the drum 40 gradually and automatically to-build up the diagram, it is only necessary to pull out the handle' 19 to move the shaft 18 axially, whereby the worm wheel 20385 will be engaged Aby a clutch as shown in Figure 9 and thus move the shaft 15 in a certain relation to thev speed of the shaft and at a much lower speed than that of the engine.

rlhis process, of course,gives1 diagrams that.v 90

ino

`used in takin the diagram in FiOure 4.

Figure 10, lis a lower loop diagram obtained by using a light spring 38 in the indicator with a suitable stop arranged tok protect the pencil motion and the light spring. Such a diagram shows clearly whether or not the exhaust and inlet valves are of proper size and whether or not they are properly operated. Vhile this lower loop is apparent yin Figure 4, it is here shown in Figure 10 to a larger scale, thusbringing outthe smaller variations so that they may be studied to the end that valve timing and size of parts may i. be improved; or the manifold may beimproved in size or shape. To. one experienced inthe art, it will'be apparent thatthis device will enable studies to be made that have,

the vertical movement will lindicate the in- 12in ated L) era 'll or yinfamia crease or decrease in pressure in the engine cylinder at that point.

rin important aspect of this invention consists in the tact that a simple and eliective means is provided for synchronizing the admission of pressure from any cylinder ol an engine tor the operation of one of the elements of the recording ineens With the operation ci" the other element or" the recording means. rlhis is coupled With the provision ot a. means for driving lthe second element of the recording means in exact synchronism with the movements of the en gine piston and crank shaft.

.rler accomplish these results, ive have provided a means for operating one element of the recording means Which is prei'- erably in the form of a. crank disk and pit- The crank disk and the pitman in turn operate a.v cross-head which is used to operate a cord for actuating the drum ot the recordinOv means. The pitnian and the crank Aot our recording means naturally has the same motion as the piston rod and crank of the engine. Furthermore, this pitman and crank are delinitely proportioned With relation to the piston and crank of the engine to have t-he same ratio of movement thereto.

Our structure is such that the pitman and crank of the recording mechanism may be adjusted. to dead center position. lhen they are in this dead center position, owing to heir connection With the crank shaft oie the g Lne crank shaft ot thc engine and ne ,if @ton and piston rod ot the engine are also in dead center position. The pitman ai d crank are so placed that it may be visually determined When they are in dead center position. y

The encil oli the recording means is opertently operated by pressure from a cylinder. lt is important to have the operation of the pencil properly synchronized with the operation of the drum. Therefore, inasmuch as Ythe piston and the crank are initially set at dead center position, it is desirable to have the valve Which is intermittently opened to admit the pressure to the pencil operating` piston arranged in such relation to the operating means for such valve that the valve Will open at the time the piston rod and l; therefor is in dead center p ition. this reason, t e cam which operates. the said valve-is adjustably connected to the driving shaft ol' the engine. rlhis is accomplished by the ot one disk Which is directly connected to the drivinfr shaft o'l the engine and Which is superimposed upon a second disk which is connected directly to the cam. These tivo disks are rotatably adjustable With renition to each other.

After the pitman and crank disk arein dearL center position, the driven disk which is direct j connected to the cam is adjusted so piston Whichis in turn intermit- Y that the cam will open the valve at the dead center position of the engine. A. means has been provided for properly fixing the position of this driven disk so as to ensure that this coincidence of position between the pitman and the crank disk and the cam and the valve which it opens may be readily obtained. This means takes the form oitl pin holes in the driven disk and a pin supporting lug 57.

lt Will be seen, With this structure, it is dily possible to delinitely position the pitnian and crank With relation to the engine piston rod and crank and, at the same time, to detinitely position the cam with relation to such engine 1'ston rod and crank. lllhen these delinite positions are initially obtained, it Will be apparent that all backlash or lost motion, it any, should be taken out of the mechanism and out 01"' the drive to the engine in order to have the device correctly timed. li this is done, correct timing Will result.

ln changing over from one cylinder to another cylinder, it is necessary that the pitinan and the crank disk be so adjusted that they Will be in dead center position at the same time that the piston rod and crank of the new cylinder are in dead center position. lt is also necessary that the cam be adjusted to open atdead centerposition. The pitman and crank disk are adjusted by connecting one end or" the pitman to another hole in the crank disk. The cam is then adjusted as previously described.

lt will be understood that the discussion so lar has dealt with cylinders which are in normal position of horizontal alignment. Where the cylinders are oiise'h'it is necessary to us-e an offset adjustment. This is effected yby turning the slid-e 29 about the pivot 35 and then securing it in proper position.

XWhen the device is in operation, the openings of the valve may be progressively ,changed so as to occur at successively earlier ing in either direction desired.

The movement of this differential housing may, however, be effected to progressively change the instant of opening of the valve so as to cause it to occur at successively later points in successive cycles by automatically operated mechanism. rl'his mechanism is th ivorm 2O andthe Worm gear 2l, rendered eliective by the proper operation oi. the clutch on the shaft 18.

Having thus described our invention, what `We claim is: f

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the pitman and crank of said mechanism being of the same proportion as the connecting rod and the crank of the engine being tested, said mechanism' being driven from the engine by means of speed reduction gearing( 2. A device for indicating the pressure in engine cylinders comprising a means' operable by thepressure from a cylinder for controlling one element of arecording means, a pitinan and crank mechanism for operating the other element of such recording means, the pitman and crank of said mechanism being of the saine' proportion as the connecting rod and the crank of the-engine being tested, saidV mechanism being driven from the engine.

3. A. device for indicating the pressure in engine cylinders comprising a means operable 'by the pressure from the cylinder for controlling one element of a recording means, a pitman and crank mechanism driven by the engine for operating the other element of said recording means, means for operating said means and said mechanism in timed relation to each other, means for varying cycle periods which are being measured, and means for reducing the speed of operation ot said mechanism with relation to the engine speed.

1l. In a device for indicating the pressure in engine cylinders comprising a means operable by the pressure from a cylinder for controlling one element of the recording means, and mechanism driven' by the engine for operating the other element of such recording means, mechanism for aligning the parts to insure accurate relation before starting,comprising relatively' adjustable drive and driven disks and settingpins.

5. A. device for indicating the pressure in lengine cylinders comprising a means'operable by the pressure from arcylinder for controlling one element of a recording means, a pitman andv crank mechanism driven by the engine Jfor operating the Aother element of Y. such recording means, means tor operating said means and said mechanism in timed relation to each other, and means for automatically varying the cycle periods which are being measured. Y i" 6. A device for indicating the pressure in engine cylinders comprising a pitman and crank operable from the engine at aY reduced speed, a crosshead operable by said pitman,

a slide tor said crosshead, and means for aligning .said slide, crossliead, pitman and crank. c

7. In a device Jor recording the pressure in a.. plurality' of cylinders, `comprising a recording means, a means for utilizing the pressure 'from a cylinder for operating one Velement ofthe recording means, a cam element operable to periodically actuate said last named mea-ns, and means for adjusting said cam element comprising a drive and a driven element relatively 'movable with respect to each other, and means Y'for securing said drive events in a plurality of engine cylinders coing,

prising a recording mechanism and means tor adjusting said recording mechanism from a position wherein it operated to record the pressure eventsin one cylinder in synchronism with the movement of the piston in that cylinder from a predetermined position to a position wherein it` will operate to record lthe pressure events in another cylinder in synchronism with the movement of the piston in that cylind'eiifrom a predetermined position without stopping the engine. Y

l0. A device for recording the pressure events in a plurality of engine cylinders comprising a recording mechanism and means` for adjusting said recording mechanism trom a position wherein it operated to record the pressure events in one cylinder in synchronism with the movement of the piston in that cylinder from a predetermined position toa position wherein it will operate to record the pressure events in another cylinder in synchronism with the movement ot the piston p in that cylinder from a predetermined position without stopping the engine, said record-V ing means being operative over a succession ofcycles, and means for adjusting said recording mechanism to eiiect recording of ditlerent parts ot successive cycles.

11. A device `for indicating the pressure in engine cylinders comprising a means actuable by the pressure from an engine cylinder for operating one element of va'recordiiig means and mechanism driven by the engine for operating .thelother element ofV a -recording means, said mechanism embodying a connecting rod and crank, the ratio between the length of a connecting rod and the throw ofV the crank being the same as the ratio be-V Y tween the length Voit the connecting rod and the throw of the crank ot the particular engine to [which the indicating device 'is attached.

Vl2.V AA device for indicating the pressure in engine cylinders comprising a means actuable by the -pressure'from an engine cylinder `'for operating one element of a recording means, mechanism driven by the engine for operating the other element ot a recording means, said mechanism embodying a connecting rod and crank, the-ratio betweenV the length of a connecting rod and the throw of the crank being the same as the ratio between the length of the connecting rod and the throw of the crank of the particular engine to which the indicating device is tached, and means for adjusting the engine driven mechanism so that it will operate in synchronism with the movement of the pistons in such cylinders.

3. In a device for recording the pressure in an engine cylinder, a recording mechanism, means actuable by the pressure from a cylinder for operating one element of said reh cording mechanism, means for periodically admitting pressure from an engine cylinder to said cylinder pressure actuated means, and means for adjusting said pressure admitting means to vary the point of admission of cylinder pressure, said last named means comprising a drive and a driven element relatively movable with respect to each other and means for securing said drive and driven element together in their adjusted position.

la. in a device for recording the pressure in an engine cylinder having cooperating recording elements, a means for operating one or" such recording elements at a selected instant by pressure from the cylinder, said means comprising a valve controlled passageway from the cylinder, a means for operating the other element of the recording means comprising a pitman and crank structure driven by the engine, means for opening the valve at a predetermined instant in the cycle, means for adjusting to synchronize the pitman and crank structure with the piston and crank of the engine cylinder, and means for adjusting saidvalve opening means to synchronize the opening of the valve with the movements of the piston and the pitman.

15. ln a device for recording the pressure in an engine cylinder having cooperative recording elements, means for actuating one of said recording elements at a predetermined instant by pressure from the engine cylinder, means for operating the other of said recording elements by the movement of the piston operating in said cylinder, said first means comprising a cam operated valve and said second means comprising a crank and pitman structure, and means for positioning said cam and said pitman structure so that the valve is open and the pitman structure is on dead center with the engine piston at the same time.

i6. In a device for recording the pressure in an engine cylinder having cooperative recording elements, means for actuating one of said recording elements at a predetermined instant by pressure from the engine cylinder, means for operating the other of said recording elements by movement of the piston operating in said cylinder, and gauging means for starting said last two means in predetermined positions with relation to each other and to the position of the piston in said cylinder.

17. In a device for recording the pressure in an engine cylinder having cooperative recording elements, means including a valve and operating means therefor for actuating one of said recording elements at a predetermined instant by pressure from the engine cylinder, a pitman and crank structure for operating the other of said recording elements b y the movement of the piston operating in said cylinder, a means for gauging the emr-ting position of said first means to determine the open position of the said valve, and a means for gauging the starting position of said pitman and crank structure, said last two means being effective to ensure that the said valve will be in open position when the pitman and crank structure and the piston are in dead center positions.

i8. A device for indicating the pressure in engine cylinders comprising a means operable by the pressure from a cylinder for controlling one element of a recording means, a pitman and crank disk for operating the other element of such recording means, a cross-head operable by said pitman, a slide for said crosshead, and means for securing one end of said pitman to said crank disk in various positions so as to synchronize the pitman and crank structure with the piston and crank of the engine cylinder.

19. A device for indicating the pressure in engine cylinders comprising a means operable by the pressure from a cylinder for controlling one element of a recording means, a pitman and crank for operating the other element of such recording means, a cross-head connected to one end of said pitman, a guide for said cross-head, said pitman, crank and cross-head being adjustable to permit alignment thereof to synchronize their relative positions with the position of the engine piston, connecting rod and crank in the particular cylinder whose pressure is to be indicated.

In testimony whereof we hereby aiiiX our signatures.

HAROLD M. JACKLIN. CHARLES P. ROBERTS. 

